Add the apples and water to a large pot or dutch oven over medium-low heat. Bring to a simmer and cover, allowing to cook on low heat for 10-15 minutes.
Use a potato masher or blender to puree the fruit and add it back to the pot. Add the lemon juice, cinnamon and sugar. (note: I used very sweet apples for this recipe. If you use tart apples you will probably want less lemon juice and more sugar.)
Continue to cook for another 10 minutes to allow the sugar to dissolve.
Use a food mill or fine mesh strainer to create a very smooth puree. It's fine to leave some fibrous apple pulp behind (I lost at least 1 cup in the food mill).
Preheat your oven to the lowest possible temperature. The original recipes states 140 degrees F. My oven only goes as low as 170 so that's the temperature I used.
Line a baking sheet with microwave-safe plastic wrap (for reference, mine is 13x18. You can also use two smaller sheets). Pour the puree on top and use a spatula to spread the mixture as evenly as possible.
Allow to cook in the oven for 8-12 hours until the fruit is completely dried out. Mine took approximately 9 hours, you may need more time if the temperature is lowered. I let it cook overnight.
Allow the fruit leather to cool. I trimmed the ends with scissors (including the plastic wrap) so they look pretty and then cut into strips of your desired size. I chose to make 3 long, large strips.
Leave the fruit leather attached to the plastic wrap until its ready to be eaten.
Adapted from Simply RecipesApples vary by sweetness and tartness. You can omit the sugar altogether if using very sweet apples. Feel free to adjust the lemon juice and sugar to taste.